There have been numerous efforts by many inventors and engineers to create a continously variable speed conical friction drive mechanical transmission wherein a nonslipping line contact between the driving and driven surfaces is realized. The nonslipping line contact is the most important issue in the friction drive system because it enables the mechanical transmission to transmit much greater power by the friction drive method compared with the point contact friction drive that is employed in all existing variable speed friction drive systems with few exceptions. according to mathematical principles, a nonslipping line contact between the conical surfaces under frictional contact is possible if and only if all conical surfaces involved in the friction drive have a common apex point. It is theoritically impossible to satisfy such a condition when one attempts to construct a friction drive including a pair of coxially disposed conical surfaces and a plurality of cylindrical or conical rollers shiftably confined therebetween. This is the exact reason why everyone has failed to come up with a nonslipping line contact continuously variable speed friction drive system.
The primary object of the present invention is to provide a stepwise variable speed mechanical transmission of a conical friction drive type wherein the principle of nonslipping line contact friction drive is realized.
Another object of the present invention is to provide a nonslipping line contact conical friction drive that includes a built-in clutch system.
A further object of the present invention is to provide a stepwise variable friction drive employing different sets of friction rollers for different speed transmissions.
Yet another object of the present invention is to provide a stepwise variable mechanical transmission comprised of inner and outer conical surfaces providing a series of conical frustum shell spaces therebetween and a plurality of sets of conical frustum rollers wherein each set of conical frustum rollers are disposed within each conical frustum shell space in such a way that all conical surfaces involved in the friction drive in each conical frustum shell space has a common apex point.
Yet a further object of the present invention is to provide means for establishing the frictional contact between the set of conical frustum rollers and the inner and outer conical surfaces confining thereof for one set of the conical frustum rollers in one conical frustum shell space at one time.
Still another object of the present invention is to provide means for relieving all frictional contacts between the set of conical frustum rollers and the inner and outer conical surfaces confining thereof for all sets of conical frustum rollers.
Still a further object of the present invention is to provide a mechanical transmission of high power transmission capability at an economic cost.
These and other objects of the present invention will become clear as the description thereof proceeds.